Outraged Republicans pointed to claims that one of five former Guantanamo prisoners traded for American Sgt. Bowe Bergdahl tried to contact the Taliban as further evidence that the Obama administration made a "bad deal."

The White House and Pentagon, once again, on Friday defended the terms of that trade and insisted that all five former detainees are in Qatar and accounted for -- and have not returned to the battlefield.

Asked if the Obama administration has any regrets over the Bergdahl-Taliban trade, White House Press Secretary Josh Earnest said: "Of course not." He said they made the swap last year based on the principle that nobody in uniform "is left behind."

But Sen. Kelly Ayotte, R-N.H., in an interview with Fox News, raised concerns that the five freed fighters might indeed be planning to return to the battlefield in the coming months, particularly after strict monitoring in Qatar is over.

"What happens then?" Ayotte asked. "Never mind that they're already attempting to re-engage and obviously making communications to do so."

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The senator pushed anew for legislation she has crafted that would suspend transfers of detainees assessed to be high- or medium-risk.

On Thursday, a U.S. official confirmed to Fox News that one of the five Taliban prisoners traded last year for Bergdahl had been intercepted making phone calls to the Taliban. Pentagon spokesman Rear Adm. John Kirby went further Friday, saying "at least one" was involved in "potential re-engagement."

Rep. Michael McCaul, R-Texas, chairman of the House Homeland Security Committee, urged Obama to halt the transfers out of Guantanamo in response. "How many wake-up calls does the president need? These actions are putting American lives at risk," he said in a statement Thursday.

Earnest said Friday the monitoring efforts for the so-called Taliban 5 "have been updated" to reflect concerns about their contacts with terror groups.

He said the administration remains confident the measures in place to keep watch over those five former detainees "substantially mitigate" the threat they pose to U.S. security. He said all are in Qatar and being monitored, and none has engaged in any "physical violence."

"None of these individuals has returned to the battlefield," Earnest said.

Kirby also said Friday the U.S. is still confident those five detainees pose minimal risks as they remain under supervision in Qatar.

"We remain confident, as we were when we sent them there, that the assurances we've received are sufficient enough to help us mitigate any future threat that these individuals might pose," Kirby said.

Amid the debate over the former detainees, the Taliban flexed their muscle again on Thursday in Afghanistan, just weeks after the end of the U.S. combat mission.

On Thursday evening, an attacker infiltrated a military base at Kabul's international airport, killing three American contractors. A Taliban spokesman claimed responsibility. Though the Pentagon is not confirming who was responsible, a spokesman said Friday the attacker was in an Afghan uniform and was subsequently killed.

Kirby said it's a "tragic and grim reminder that Afghanistan still remains a dangerous place in many ways."

The White House this week, meanwhile, took pains to avoid calling the Taliban a terrorist organization, at first labeling them an "armed insurgency" before acknowledging that they are on a formal listing of terror groups.

While the Taliban is not listed on the State Department list of foreign terrorist organizations, it is on the Treasury Department's list of "specially designated global terrorist," dating back to a 2002 executive order. Earnest acknowledged Thursday that they "do carry out tactics that are akin to terrorism, they do pursue terror attacks in an effort to try to advance their agenda." However, he said they are not like Al Qaeda in that they don't have "aspirations that extend beyond just the border between Afghanistan and Pakistan."

Kirby claimed Friday that the White House was not trying to say the Taliban are not terrorists. He, too, offered a nuanced explanation.

"In fact, I think my colleague and the White House made it clear that they use terror tactics to some degree to exert their influence," Kirby said. "They are not designated a foreign terrorist organization and for purposes of the U.S. armed forces in Afghanistan they are considered an armed insurgency, but nobody is discounting the kind of violence that they're capable of and remain capable of."

According to the United Nations, at least 3,188 Afghan civilians were killed in the war in 2014 -- at least three-quarters of them by the Taliban. It was the deadliest year on record for non-combatants, according to the U.N.

The U.S. combat mission in Afghanistan has officially ended, but 10,000 U.S. soldiers and military contractors still remain in the country, mostly in advisory and security roles.

At Guantanamo, 122 prisoners remain at the detention camp, with 35 of them recommended for indefinite detention. The Obama administration has been looking to close the prison, with dozens of prisoners who have not been charged set for release once a county agrees to take them.